Question

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1. A car starts from rest and attains a velocity of 36 km/h in 40 s. The driver applies brakes and slows down the car to 5m/s in 10 s. Find the acceleration of the car in both the cases.

Solution:

Hint: 1 km/h = 5/18 m/s

Case 1:

Initial velocity, u= _________

Final velocity, v = __________

Time t = __________

Acceleration, a = v-ut

= ___________

Case 2:

Initial velocity, u= _________

Final velocity, v = __________

Time t = __________

Acceleration, a = v-ut

= ___________

Answer 1

Dear Student
$$\begin{gathered} Initialvelocity=0 \\ final=36\times \frac{5}{18}=10m/sec \\ time=40sec \\ v=u+at \\ 10=a*40 \\ a=0.25m{s}^{-2} \\ Finalvelocitynow=5m/sec \\ time=10sec \\ 5=10+a\times 5 \\ a=-1m{s}^{-2} \\ REGARDS \end{gathered}$$